Process of making crystals containing mesothorium.



taneously in the course. of time, causes the action has been used in theseparation of FREDERICK sonny, OF.

arena enrich erase'oii", SCOTLAND.

iPROCESS OF MAKING CRYSTALS COhTTAINING ME$OTHOBIUIVL 1,03 ",sos.

No Drawing.

Specif cation of Letters Patent.

iatented July 2, 1912..

Application filed October 4, 1911.- Serial No 652,719.

To all whom it may concern:

Be it known that I, Fnnnnmon Sonny, a subject ofiHis Majesty the King ofGreat Britain, and a resident of Glasgow, Scotland have invented acertain new and useful Improvement in Processes of Making CrystalsContaining Mesothorium, of which thefollowing is a specification.

Thewbject of the present invention is firstly, the separation ofmesothorium from monazite sand as a crude product in the course of themanufacture of thorium compounds therefrom, and secondly, thepreparation in concentrated form of the mesothorium contained in this orother crude products containing it,

By mesot horiuin is meant the constituent of thoriu'm mineralsdiscovered by Hahn (Eerie/1,250 dc? Denise/zen Chemise/Len GcseZZso/mfz,i907, alt), p 11162,) which, together with the products it producessp0ngreater part of the radioactivity of these minerals in the samesense as radium is the constituent which, with its products, causes thegreater part of the radioacti\-'ity of minerals containing uranium.

Commercial thorium compounds are free from 2iesotlua-iiuu when firstprepared, but in the course of time mesothoriuln is produced in them.For this reason the ash from old iueaiulesreut gas mantles containsniesothorium, which may be separated during the process for the recoveryof the contained thoriun'i by the invention herein described.

T he intention is based upon the discovery I have made thatn'iesothorium and barium are extremely closely related in their entirechemical nature. Mesothorium resembles radium in this respect and can beseparated by the use of barium from all other substances.

It is common knowledge that one particular compound of barium, namelybarium sulfate, is used as an adsorbent for many substances, partiallywithdrawing some from a mixture of substances in solution and leavingothers in, the solution, and that this mixtures of radioactivesubstances from one another. This adsorption process in gen eral effectsonly a partial separation and'is variable in its action. as it dependsupon a ariety of conditions which cannot be exactly controlled, such asthe size of the parcompounds by precipitating barium sulfate.;;

in the solution. He attribiitcd this separasulfate. n

The present inye tion relates to a practical process for the separationor; mesothorium and its preparation in concentrated form from a mixture,even as complex and as poor lll'IIlQSObllOlllllD monazite sand, andconsists in utilizing the discovery Ihaye made that .the action ofbarium in the separation of mesothorium is not a physical or adsorptionaction confined to the one compound barium sulfate, but is due to anal;most complete chemical similarity between mesothorium and barium. If theseparation of mesothorium with barium sulfate were due ,to an adsorptionas soon as the barium sulfate were converted into some other com poundof barium it could not be foretold win any chemical operation with thesaid compound whether the mesothoriumwould. ren'iaiirwith the barium ornot. Whereas the knowledge of the fact that mesothorium and barium arechemically closely related.

enables an expert chemist, even though ignorant of the special means ofdetection, identification, and quantitative estimation of radioactivesubstances, to separate mesothorium from a mixture by adding theretobarium if not already present and separating out the barium fromallothei' substances.

The principle of the subsequent separation of the mesothorium; from thebarium is based upon the additional discovery I tion of anadsorptionactionoft-he barium have made that in so far as mesothoriumdiffers from barium it resembles radium and can so be concentrated bythe fractional crystallization of the purified barium chloridcontaining: nesothorium. This chemical resemblance. which so far as Iknow is perfect, between mesothorium and radium could not possibly havebeen inferred or deduced from existing knowledge, but-its disrtclosureherein puts any chemist able to separate radium.

from the radium residues of uranium minerals in a position to separatemesothorium 'rium therein becomes at from thorium minerals. WVhenmonazitesand is' treated in the ordinary way in the manufacture ofthorium therefrom the mesothorium therein, on account of its practicallyinfinitesimal quantity, and because of the absence therein of barium inpractically separable quantity, behaves chemi- .cally indefinitely,being partially removed pounds, without detriment to'this manufacture.The first stage/in the manufacture of thorium compounds is to-heatmonazite sand with excess of sulfuric acid, and to stir the cooledproduct with cold water, whereby the monazite is dissolved. A muddyliquor is s'oobtained which may be'without "difiiculty poured off from,the heavy residue of unattached sand. This muddy. liquor when left tostand deposits a small sediment. In the process, herein described, asmall quantity say one thousandth part by weight of say barium carbonateis added, either to the monazite sand, or to the. mix ture of monazitesand and acid before heating. When the monazite sand is treated asdescribed, this added barium is deposited as barium sulfate with thesediment from the muddy liquor before referred to. This sedi ment thencontains the mesothorium present in the mineral and will be referred tosubsequently as the crude mesothorium product.

Another way of performing the same operation, which is applicable whenthe mona- 'zitc sand is ground before treatment, is to add to the clearsolution of monazite in sulfuric acid and water, obtained as described,a solution containing a small quantity of a barium compound, witheflicien't stirring, and in this casealso the mesothorium isprecipitated with the barium sulfate. The quantity of barium saltsnecessary to be added to effect a good separation is regulated chieflyby the volume of the liquids treated and by the solubility of bariumsulfate therein. The quahtitymust not be so small that any practicallyimportant fraction of the barium remains in solution, but may be made aslarge as is necessary to give a precipitate of convenient amount. Onehundredth part of the weight of nionazite sand or raw material is a safeproportion o barium salt but this amount may be reduced usually asexperience of the process is gained. \Vhcn the addition is made to thesolution as descrilwd, the solution of the avoided.

barium salts must be dilute and mustbe added slowly with efficientcontinuous ag tation of the whole bulk of the solution to which it isaddedfto avoid a merely local mesothorium in the crude products derivedfrom minerals containing thorium, either in the manner described or inother ways, the material is treated chemically by the usual processeshaving for their object the separation of the continued barium with the.

mesothorium from all other substances.

Should the crude products not contain suificient barium a small quantityis added at the commencement of enduring the concentration process.

purities present and the. equipment and character of the factory inwhich the work is done, but the object of the process is always toseparate the whole of the contained barium chlorid together with themesothorium from all the substances present which are different frombarium in cal properties.

As an example the crude mesothorium chemi- The exact method followedwill depend upon, the nature of the crude material, the nature andamount of the 1mmaterial obtained from monazitesand or.

from gas mantle ash will be considered. The first step is to dissolveit. Solution of the sulfates may be effected by conversion intocarbonatcs,ieither-by fusion with so dium carbonate, or by long boilingwith concentratedv solution of sodium carbonate; The product is washedfree from sulfates and dissolved in hydrochloric acid. The product willbe referred chlorids. Y

If preferred solution. may be effected by heating with carbon," andtreatment of the sulfids formed with hydrochloric acid whereby the longwashing to free the carbonates from sulfates in the carbonate process isfrom the barium chlorid with which his mixed may be effected byfractional crystallization of the purified barium chlorid, in the samemanner as in the known process for the concentration of radiun frombarhun chlorid. \Vhen barium cilorid con i aining mesothorium iscrystallized the mesoto as the' crude' The crude barium chlorid isthenthorium is concentrated in the crystals, and

preparations of any desired degree of concentration and on the otherbarium chlorid of an desired de ree of innoverishment.

The latter preparations need not be entirely freed from mesothorium butmay be used with advantage instead of fresh barium in the Working up offresh thorium mineral.

\Vhat I claim is Process of making crystals containing mesothorium,consisting in treating monazite sand or other material containingmesothorium with any compound of barium and precipitating the barium asbarium sulfate which carries with it the mesothorium, re-.

converting the barium and mesothorium into soluble form and separatingthem from the other constituents and fractionally crystallizing saidbarium and mesothorium, the latter being concentrated in the crystalsfirst deposited.

In testimony whereof I have hereunto set 'my hand in. the presence oftwo subscribing Witnesses.

' FREDERICK SODDY. Witnesses:

ALEXANDER F LEEK,

A. H. BODLE.

